Identification of different gene expression patterns in low and high gradenon-Hodgkin's lymphomas by differential display

We have compared the patterns of gene expression in non-Hodgkin's lymphoma (NHL) biopsy samples from patients with either low grade or high grade dise ase, by the polymerase chain reaction (PCR) based technique of differential display. By using a combination of 30 primer pairs we estimate that we wer e able to survey over 3,000 genes expressed in these tissues. In this study we compared a group of three low grade follicular centre lymphomas with a group of two high grade diffuse large cell lymphomas and scored only those PCR products that were represented in all samples of each group. In doing s o we were able to avoid many of the problems associated with the occurence of false PCR-positives. 139 differences were then scored as representing ge nes which may be differentially expressed during the transformation from lo w to high grade disease. However, as many of these might simply reflect cha nging populations of cells, we focused on only those genes which appeared t o be expressed exclusively in either low grade or high grade disease. We ha ve identified 14 such genes, of which 10 were low grade specific and 4 were high grade specific. This approach therefore appears to offer a systematic method for the identification and characterisation of differentially expre ssed genes, which are characteristic of different NHL sub-types.